共查询到20条相似文献,搜索用时 15 毫秒
1.
采用数值模拟方法对比研究了160 mm×160 mm铸坯电磁搅拌参数对钢液搅动和结晶器内流场的影响。结果表明,在频率(1.0~5.0 Hz)条件下,磁感应强度随着频率的增大而减小,且变化量较大。钢液内电磁力沿圆周方向对称分布。在电流(200~500 A)条件下,磁感应强度随着电流的增大而增大。结晶器内半径方向上电磁力波动较大,存在多个波峰,波峰最大的位置都在距结晶器铜管15 mm处,与搅拌电流的大小无关,电磁力随电流的增大而增大。小方坯结晶器电磁搅拌频率应控制在3~4.5 Hz,电流大小应控制在300~500 A。 相似文献
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利用ANSYS软件对160 mm×160 mm小方坯凝固末端电磁搅拌器所产生的电磁场分布进行了模拟。计算了小方坯内部磁场分布情况,同时计算出在不同搅拌电流条件下的铸坯凝固末端凝固前沿钢液液芯所受的电磁力与钢液的转速。结果表明,铸坯凝固前沿磁感应强度、电磁力及钢液转速均随着搅拌电流的增加而增大。结合实际生产情况,确定凝固末端液芯半径为175 mm,电磁搅拌频率为6 Hz时,最佳搅拌电流为400 A,此状态下凝固前沿由电磁力引起的钢液最大转速为12 r/s。 相似文献
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利用有限元分析软件,建立了380 mm×280 mm大方坯结晶器电磁搅拌的三维数学模型,系统研究了电磁搅拌工艺参数(电流250~500 A,频率1.5~3.0 Hz,结晶器铜板厚度34~40 mm)对结晶器内电磁场的分布影响。结果表明,结晶器内磁感应强度沿铸流轴向呈"两端小、中间大"分布;电流从350 A增大到500 A,搅拌器中心的磁感应强度呈线性递增;频率由1.5Hz增大到3.0Hz,搅拌器中心磁感应强度仅减小0.001 5 T;随着结晶器铜板厚度的增大,铸坯宽面、窄面和角部的磁感应强度都减小。在实际连铸U71Mn重轨钢中,电流应该维持在400 A以上。 相似文献
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《钢铁研究学报(英文版)》2014
A final electromagnetic stirring model was developed for billet continuous casting of high carbon steel using the commercial software ANSYS and CFX, and the numerical model was validated by the magnetic flux density measured under a Teslameter CT-3. The magnetic flux density and fluid flow in the liquid pool at the location of final electromagnetic stirring (F-EMS) were calculated by the present numerical model. Meanwhile, the plant trials were carried out to determine the optimum current intensity and frequency of F-EMS for the continuously cast billet of high carbon steel. The numerical results show that, through increasing the current intensity by 100 A, the corresponding increases of magnetic induction intensity, tangential electromagnetic force and flow velocity at the solid/liquid interface in the strand are 0.025 T, 1933 N/m3 and 6.9 cm/s, respectively. Moreover, the industrial trial results showed that for the continuously cast billet of 60 steel, the optimum current intensity and frequency of F-EMS, which is 8.2 m from the meniscus, are respectively 380 A and 6 Hz. With the optimum F-EMS parameters, the significant improvement of center segregation of billet is achieved, and the center carbon segregation index in billet reaches 1.04. 相似文献
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《Baosteel Technical Research》2020,(2)
Using computer simulation and test measurements,the relationship between the electromagnetic properties of an electromagnetic stirring roller and the roller structure parameters was analyzed and compared. The distribution of the magnetic field,magnitude of the electromagnetic force,and matched-load characteristics were systematically investigated at different parameter values for the induction coils,iron core,shield,and roller sleeve.The results indicate that the change in the electromagnetic force with stirring frequency is non-linear and has a maximum value higher than 10 Hz; the electromagnetic force largely depends on the diameter of the core; and there is a mutual restriction relationship between the two-phase imbalance and the electromagnetic force. 相似文献
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New measurement techniques for local velocity, magnetic field, and current density have been applied to the study of electromagnetic
and hydrodynamic phenomena in a coreless induction furnace containing an aluminum alloy. The action of electromagnetic shields
on the intensity and the structure of the liquid metal flow is reported. It is shown that the direction of the fluid flow
and the number and sizes of the recirculating cells may be significantly modified; the electromagnetic stirring may also be
practically canceled. The influence of the dimensions of the screens on the structure of the liquid metal flow is examined.
Finally, the modification of the fluid flow phenomena is explained by the evolution of the electromagnetic force patterns. 相似文献
8.
Mathias Dubke Karl-Hermann Tacke Karl-Heinz Spitzer Klaus Schwerdtfeger 《Metallurgical and Materials Transactions B》1988,19(4):581-593
A model is presented to compute the electromagnetic force fields and fluid flow fields in electromagnetic stirring of continuously cast strands with rectangular cross-section. The model involves the solution of the Maxwell equations, the Navier-Stokes equations, and the transport equations for the turbulence characteristicsk and e. The procedure of depth-averaging is applied in the treatment of several three-dimensional flows. Experiments were performed to check the computations using mercury as fluid. The spatial distribution of the magnetic induction and of the force density was determined for the laboratory inductor used in the stirring experiments. The flow velocity was measured photographically or with a drag probe, respectively. The agreement between experimental and theoretical data was found to be within 25 pct. It is concluded that the theory is sufficiently reliable to predict the flow fields in electromagnetic stirring of steel strands. In Part II of this paper the model is applied to analyze stirring situations in continuous casting of steel. 相似文献
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Mathias Dubke Karl-Hermann Tacke Karl-Heinz Spitzer Klaus Schwerdtfeger 《Metallurgical and Materials Transactions B》1988,19(3):581-593
A model is presented to compute the electromagnetic force fields and fluid flow fields in electromagnetic stirring of continuously
cast strands with rectangular cross-section. The model involves the solution of the Maxwell equations, the Navier-Stokes equations,
and the transport equations for the turbulence characteristicsk and e. The procedure of depth-averaging is applied in the treatment of several three-dimensional flows. Experiments were
performed to check the computations using mercury as fluid. The spatial distribution of the magnetic induction and of the
force density was determined for the laboratory inductor used in the stirring experiments. The flow velocity was measured
photographically or with a drag probe, respectively. The agreement between experimental and theoretical data was found to
be within 25 pct. It is concluded that the theory is sufficiently reliable to predict the flow fields in electromagnetic stirring
of steel strands. In Part II of this paper the model is applied to analyze stirring situations in continuous casting of steel.
Formerly with Institut für Allgemeine Metallurgie, Technische Universit?t Clausthal 相似文献
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Finite Element Analysis of 3-D Electromagnetic Field in Bloom Continuous Casting Mold 总被引:2,自引:0,他引:2
Three-dimensional finite element model of electromagnetic stirrer was built to predict magnetic field in a bloom continuous casting mold for steel during operation.The effects of current intensity,current frequency,and mold copper plate thickness on the magnetic field distribution in the mold were investigated.The results show that the magnetic induction intensity increases linearly with the increase in current intensity and decreases with the increase in current frequency.Increasing current intensity and frequency is available in increasing the electromagnetic force.The Joule heat decreases gradually from surface to center of bloom,and a maximum Joule heat can be found on corner of bloom.The prediction of magnetic induction intensity is in good agreement with the measured values. 相似文献
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Rolls made of high speed steel (HSS) have been prepared by centrifugal casting with electromagnetic stirring. During the centrifugal casting process of HSS rolls, segregation of alloy elements occurs due to the centrifugal force either to the outer or to the inner side of the rolls depending on the relative densities of alloyed elements and molten steel. The experimental results show that the electromagnetic stirring lessens the segregation of the alloyed elements in the centrifugally cast HSS roll. Moreover, the segregation of tungsten, molybdenum and vanadium is obviously diminished with increasing magnetic intensity but the segregation of vanadium increases again when the intensity of the electromagnetic field exceeds 0.053T. The reasons for these phenomena are analysed. 相似文献
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搅拌器的结构参数对钢液内电磁场和流场分布的影响 总被引:7,自引:1,他引:6
利用ANSYS5.6软件对单侧线性电磁搅拌作用下钢液内的电磁场分布和流场分布进行了数值模拟,分析了搅拌器的结构参数对钢液流动状况的影响,结果表明,在搅拌器长度,线圈匝数及电流强度均相同的条件下,采用集中绕组的搅拌器所产生的电磁场最弱,而重叠绕组搅拌器和克兰姆绕组搅拌器的电磁利用率较高,所产生的磁场强度越大,钢液的流动速度和紊流动能均较大;此外,尽管磁轭不影响电磁场的分布趋势,但却显影响磁场强度的大小,所以,在数值模拟中应当考虑磁轭的存在,当搅拌器极距和其它参数一定时,增加搅拌器长度有利于扩大搅拌的作用范围,但对提高搅拌无明显效果,在搅拌器长度和其它参数一定的情况下,增大搅拌器的极距却不影响搅拌的作用范围,但却使搅拌强度明显提高。 相似文献
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以特殊钢圆坯连铸为研究对象, 建立了研究凝固末端电磁搅拌作用效果的三维耦合数值模型.利用分段计算模型获得末端电磁搅拌区域钢液流动与凝固的实际状态, 并采用达西源项法处理凝固末端钢液在糊状区的流动, 研究了不同电磁搅拌工艺参数下的电磁场分布及钢液的流动与传热特征.通过测量搅拌器中心线磁感应强度和铸坯表面温度验证了模型的准确性.研究结果表明: 电流强度每增加100 A, 搅拌器中心磁感应强度增加19.05 mT, 电磁力随着电流强度的增加显著增大.在20~40 Hz范围, 随着电流频率的提高, 中心磁感应强度略微下降, 但电磁力仍有所增加.在搅拌器区域, 液相穴内的钢液在切向电磁力的作用下旋转流动, 其切向速度随着电流强度和频率的增加而变大.末端电磁搅拌可促进钢液在圆坯径向的换热, 随着电流强度和频率的提高, 铸坯中心轴线上的钢液温度降低, 同时末端搅拌位置处的中心固相分率增加. 相似文献
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The electromagnetic field and flow analysis model were developed to simulate the electromagnetic field and the flow pattern in a vertical curved continuous slab caster with the in-roll type strand electromagnetic stirring.The transient electromagnetic field distribution and the induced electromagnetic force were numerically described.The effects of stirring current,stirring frequency,and different stirrer configurations on the electromagnetically driven flow field in the strand were investigated and the optimization of the stirring parameters was discussed by performing a relative comparison of numerical results.Results show that the in-roller type strand electromagnetic stirrer(SEMS)pair generates the fluctuating magnetic fields,penetrating through the cast slab and periodically parallel shifting along the slab wide face with time evolution.The transient induced electromagnetic forces travels toward the magnetic flux shifting direction.Different stirring parameters(i.e.current and frequency)and stirrer configurations affect the stirring strength and the flow recirculation pattern in the strand,which are closely related to metallurgical performances of the stirrers.There is an optimum frequency to obtain the maximum stirring.The present model provides a relatively theoretical insight into the in-roll type strand electromagnetic stirring system for best operating. 相似文献
18.
Heping Liu Mianguang Xu Shengtao Qiu Hui Zhang 《Metallurgical and Materials Transactions B》2012,43(6):1657-1675
In this article, an electromagnetic field simulation and a flow analysis model are performed to describe the three-dimensional electromagnetic field distribution and the electromagnetically driven flow characteristics in a round-bloom mold with a low-frequency in-mold rotary electromagnetic stirrer. The interaction between the induced flow and the inertial impinging jet from a straight-through submerged entry nozzle (SEN) of the caster is considered. The effects of stirrer current and frequency on the electromagnetic field and the flow in the round-bloom mold are investigated, and a strategy to optimize the stirring parameters is proposed. The results show that the distributions of magnetic flux density and electromagnetic force magnitude are nonuniform in a three-dimensional electromagnetic stirring (EMS) configuration. There exists a significant axial induced component of electromagnetic force. The flow in the in-mold EMS system is characterized by a dominant swirling movement at the transverse sections, coupled with the recirculating flows in the axial direction. An upper recirculation zone and a lower recirculation zone with the reverse melt flowing are found near the strand wall at the axial location close to the middle of the stirrer, and another recirculation zone is formed due to the interference of the induced flow with the jet from SEN. The meniscus surface has a swirl flow, and the meniscus level rises near the bloom strand wall and sinks around the SEN wall. All of these flow features are closely associated with metallurgical performances of the in-mold rotary stirrer. With the increase of stirring current and the decrease of frequency, the magnetic flux magnitude increases. There is an optimum frequency to obtain a peak of electromagnetic force magnitude and maximum tangential velocity. For a mold rotary EMS system, to determine the optimum stirring intensity, it is necessary to make a compromise between a larger tangential velocity and a relatively quiescent meniscus surface. 相似文献
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